Imaging Unit

Nowadays, the elucidation of molecular and biochemical processes requires its combination with investigation of cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. For centuries, progress in biological research has been connected to the development of tools and equipment that allow new insights into living matter. The invention of and improvements in optical systems were very important because exceeding the limits of the optical resolution of the human eye delivered new insights into tissues, cells and subcellular compartments on the one hand and cellular processes on the other.

The Imaging Unit of the IPB aims to support all research groups in their use of cell biological methods. Currently, at least 13 research groups of the institute are using this unit.

The unit provides:

Coordinated supervision and maintenance of equipment

Optimal training of coworkers

Maximal use of IPB investments

Updating of equipment according to state-of-the-art and to requirements of actual research

Oxylipins including jasmonates are signaling compounds in plant growth, development, and responses to biotic and abiotic stresses. In Arabidopsis (Arabidopsis thaliana) most mutants affected in jasmonic acid (JA) biosynthesis and signaling are male sterile, whereas the JA-insensitive tomato (Solanum lycopersicum) mutant jai1 is female sterile. The diminished seed formation in jai1 together with the ovule-specific accumulation of the JA biosynthesis enzyme allene oxide cyclase (AOC), which correlates with elevated levels of JAs, suggest a role of oxylipins in tomato flower/seed development. Here, we show that 35S::SlAOC-RNAi lines with strongly reduced AOC in ovules exhibited reduced seed set similarly to the jai1 plants. Investigation of embryo development of wild-type tomato plants showed preferential occurrence of AOC promoter activity and AOC protein accumulation in the developing seed coat and the embryo, whereas 12-oxo-phytodienoic acid (OPDA) was the dominant oxylipin occurring nearly exclusively in the seed coat tissues. The OPDA- and JA-deficient mutant spr2 was delayed in embryo development and showed an increased programmed cell death in the developing seed coat and endosperm. In contrast, the mutant acx1a, which accumulates preferentially OPDA and residual amount of JA, developed embryos similar to the wild type, suggesting a role of OPDA in embryo development. Activity of the residual amount of JA in the acx1a mutant is highly improbable since the known reproductive phenotype of the JA-insensitive mutant jai1 could be rescued by wound-induced formation of OPDA. These data suggest a role of OPDA or an OPDA-related compound for proper embryo development possibly by regulating carbohydrate supply and detoxification.